Master Flow AIC12 Rotary Turbine Ventilator, 12 in Dia Throat, Aluminum, Mill

Permanently lubricated track system, upper and lower stainless steel ball bearings prevents metal-to-metal contact, encased to help prevent dirt, dust, sand and other foreign materials from damaging bearings for long life, less friction, smoother spin and wear resistance. Heavy-duty steel spider braces and case-hardened steel shaft for long-lasting strength/durability. Simple, mechanically-locked, two-piece head/base for faster, easier installation. Pre-punched bottom/crimped collar of one-piece base fits tighter, makes installation easier and allows for adjustability up to 12/12 pitch without removing turbine. Extra-large flashing and head with included bottom ring for easier installation and better weather protection. Double ribbed vanes, with convex top, direct even wind-driven rain away from the unit. Dade County/Texas Department of Insurance approved. Head, heavy-duty steel spider braces for strength and durability Bottom ring included for easier and faster installation on base and great weather protection Dual bearing system, encased design helps to prevent dirt, dust, sand and other foreign materials from damaging the bearings, resulting in a smoother spin Permanently lubricated track system insures years of trouble-free spinning Special design prevents metal-to-metal contact results in less friction for a truer, smoother spin and great wear resistance Shaft, case hardened steel for long lasting strength and durability Base, pre-punched bottom and crimped collar fits tighter, makes installation easier One-piece design for easy adjustability up to 12:12 pitch without removing turbine Extra-large flashing for easier installation and great weather protection